1. Technical Field
The present disclosure relates to thin film lithium ion batteries.
2. Description of Related Art
A thin film lithium ion battery includes a case, an anode, a cathode, and a solid electrolyte layer. The anode, cathode, and the solid electrolyte layer are encapsulated in the case. The solid electrolyte is located between the anode and the cathode. The cathode includes a cathode current collector and a cathode material layer disposed on a surface of the cathode current collector. The anode includes an anode current collector and an anode material layer disposed on a surface of the anode current collector.
The current collector is used to collect the charge generated by the thin film lithium ion battery during discharge, and to connect to an external power source during the recharging of the thin film lithium ion battery. The current collectors are usually made of metal foils, such as copper foil and aluminum foil. However, the metal foils have a relatively large weight. The power density is calculated by power/weight. Therefore, a large weight of the current collector will decrease the power density of a thin film lithium ion battery. Furthermore, the metal foils may be corroded by the electrolyte, which decreases the life span of the thin film lithium ion battery.
What is needed, therefore, is to provide a thin film lithium ion battery having high power density and long life.